CF977F.Consecutive Subsequence

You are given an integer array of length $n$.

You have to choose some subsequence of this array of maximum length such that this subsequence forms a increasing sequence of consecutive integers. In other words the required sequence should be equal to $[x, x + 1, \dots, x + k - 1]$ for some value $x$ and length $k$.

Subsequence of an array can be obtained by erasing some (possibly zero) elements from the array. You can erase any elements, not necessarily going successively. The remaining elements preserve their order. For example, for the array $[5, 3, 1, 2, 4]$ the following arrays are subsequences: $[3]$, $[5, 3, 1, 2, 4]$, $[5, 1, 4]$, but the array $[1, 3]$ is not.

给你一个长度为 $n$ 的整数数组。

你需要从中选出一个长度尽可能长的子序列，使得该子序列构成一个严格递增的连续整数序列。换言之，所求序列应形如 $[x, x + 1, \dots, x + k - 1]$，其中 $x$ 为某个整数，$k$ 为序列长度。

数组的子序列可通过从原数组中删除若干（可能为零）个元素得到；你可以任意删除元素（不要求连续删除），剩余元素保持原有相对顺序。例如，对于数组 $[5, 3, 1, 2, 4]$，以下均为其子序列：$[3]$、$[5, 3, 1, 2, 4]$、$[5, 1, 4]$；但 $[1, 3]$ 不是其子序列。

The first line of the input containing integer number $n$ ($1 \le n \le 2 \cdot 10^5$) — the length of the array. The second line of the input containing $n$ integer numbers $a_1, a_2, \dots, a_n$ ($1 \le a_i \le 10^9$) — the array itself.

输入的第一行包含一个整数 $n$（$1 \le n \le 2 \cdot 10^5$）—— 数组的长度。
输入的第二行包含 $n$ 个整数 $a_1, a_2, \dots, a_n$（$1 \le a_i \le 10^9$）—— 数组本身。

On the first line print $k$ — the maximum length of the subsequence of the given array that forms an increasing sequence of consecutive integers.

On the second line print the sequence of the indices of the any maximum length subsequence of the given array that forms an increasing sequence of consecutive integers.

第一行输出 $k$ —— 给定数组中构成连续整数递增序列的最长子序列的长度。

第二行输出该最长子序列中任意一个满足条件的元素在原数组中的下标序列。

All valid answers for the first example (as sequences of indices):

• $[1, 3, 5, 6]$
• $[2, 3, 5, 6]$

All valid answers for the second example:

• $[1, 4]$
• $[2, 5]$
• $[3, 6]$

All valid answers for the third example:

• $[1]$
• $[2]$
• $[3]$
• $[4]$

All valid answers for the fourth example:

• $[1, 2, 3, 7, 8, 9]$

第一个示例的所有有效答案（以索引序列形式表示）：

• $[1, 3, 5, 6]$
• $[2, 3, 5, 6]$

第二个示例的所有有效答案：

• $[1, 4]$
• $[2, 5]$
• $[3, 6]$

第三个示例的所有有效答案：

• $[1]$
• $[2]$
• $[3]$
• $[4]$

第四个示例的所有有效答案：

• $[1, 2, 3, 7, 8, 9]$